And we found as you age, its harder and harder, even if fit, to drive overnight from 200 feet ASL, to 10,000 feet ASL and start going.. Just the dang altitude change is a bear...
I used to do it all the time, and get up and start going, as hard and far as I could, trying to get it going... one time I did a 12 mile loop according to the map, 2nd day up, and did it agian the 3rd day, all running 8-11K feet ASL, and the 4th day I could hardly move. LOL.
As I age, if nothing else, get up high 2-3 days early and even if not hiking, just camping in that air and the body gets used to it. I"ll likely die though, still pushing it as soon as I get there, as its how I'm wired.... but then again maybe by 60 or so I'll learn to chill.
Our great friends in AK, will sit in camp, while we go out and hunt... and relax and call for moose etc.... lets just say its about as common to kill one sitting in the camp chair over the years as it is to kill one in the bush. Though we have a lot more action in the bush. But I digress.
Get in shape, have extra time allowed at teh front end if possible. Aspirin regime starting a week out helped us it sure seemed.
Don't worry about the shot...
